Vitamins

Thiamin

Other name(s):

vitamin B-1, thiamin (U.S. spelling), thiamine (European spelling)

General description

Thiamin is a part of the B family of vitamins (B complex). It was the first water-soluble vitamin discovered. It is also known as vitamin B-1. Like all B vitamins, thiamin is best known for helping make energy. Beriberi and Wernicke-Korsakoff syndrome are the most common diseases linked with thiamin deficiency. But they are not common in the U.S.

Thiamin is needed for carbohydrates to break down. It helps turn glucose and carbohydrates into energy. It works with other enzymes in more than 20 metabolic processes.

Thiamin is also needed for the nervous system and the brain to work well. Because thiamin is needed for nerve function, low levels can lead to nerve problems.

Medically valid uses

Thiamin is used to treat or prevent beriberi. It’s also used to treat Wernicke-Korsakoff syndrome (WKS). This is a severe thiamin deficiency. It’s caused by a low intake of and less ability to use thiamin. It’s common in people with any of these:

Alcoholism

A severe digestive disorder

Fast-growing blood cancer

Drug use disorders

AIDS

Weight-loss surgery

Unsubstantiated claims

There may be benefits that have not yet been proven through research.

Thiamin may repel mosquitoes. It may also lower blood sugar levels in people with diabetes. More studies are needed to see if thiamin supplements can lower glucose levels in people with diabetes or lessen problems from diabetes.

It may also help improve mental stability. It’s also been used to boost appetite. It may also treat rare metabolic issues related to learning disabilities.

Recommended intake

How much thiamin you need depends on how many calories from carbohydrates you get in your diet. The more carbohydrates you eat, the more thiamin you need. Adults need about 0.4–0.5 mg for every 1,000 calories they eat.

Thiamin is measured in milligrams (mg). The RDA is the Recommended Dietary Allowance.

Group

RDA

Infants (0–6 months)

0.2 mg*

Infants (7 months to 1 year)

0.3 mg*

Children (1–3 years)

0.5 mg

Children (4–8 years)

0.6 mg

Children (9–13 years)

0.9 mg

Males (14 years and older)

1.2 mg

Females (14–18 years)

1.0 mg

Females (19 years and older)

1.1 mg

Pregnant women

1.4 mg

Breastfeeding women

1.4 mg

*Adequate Intake (AI). This is based on the average intake in healthy, breastfed infants.

Food source

Nutrient content per 100 grams

Dried yeast

15.6 mg

Pine nuts

1.28 mg

Soybeans

1.14 mg

Pork

1.1 mg

Brazil nuts

1.0 mg

Pecans

0.86 mg

Pistachios

0.67 mg

Kidney beans

0.6 mg

Lentils

0.5 mg

Hazelnuts

0.47 mg

Thiamin is not stable at high temperatures. Because of this, cooking reduces its amount in food by 10–25%. Thiamin dissolves in water. So, if you cook foods high in thiamin in water and then discard the water, you won’t get as much thiamin.

Using sulfur dioxide to preserve dried fruit will destroy the thiamin content.

Thiamin is sensitive to light. Store foods with thiamin in light-resistant containers.

Thiamin supplements may be needed for any of the below:

People with alcoholism or heavy alcohol use

People who eat diets high in refined carbohydrates

Breastfed babies whose mothers have a poor diet

People with hyperthyroidism

People with hypermetabolic problems, such as pheochromocytoma

People who had a lot of stress

People doing a lot of heavy physical activity

Women who are pregnant or breastfeeding (talk to your healthcare provider first)

Older adults with poor diets and natural decrease of absorption due to aging

Early symptoms of thiamin deficiency include:

Loss of appetite

Weight loss

Weakness

Fatigue

Confusion

Short-term memory loss

Later symptoms may include:

Pain

Numbness

Tingling

Muscle weakness

Poor coordination

Mood swings

Irritability

Depression

Memory loss

The later stages of thiamin deficiency can turn into beriberi. This includes dry beriberi, wet beriberi, and Wernicke-Korsakoff syndrome.